Sowbugs and Pillbugs

Sowbugs, pillbugs or woodlice [more pictures] normally don't harm garden plants. They feed mostly on dead organic debris. However, two situations occur that cause gardeners and homeowners some concern.

Sometimes these small land crustaceans (related to shrimp) damage tender, young garden seedlings -- their damage is similar to slug damage. This plant damage only occurs when very high populations of these critters are allowed to develop and when very young plants are present. Plant injury is pretty rare and can usually be managed.

other common names: woodlice (wood louse), lawn shrimp, rollie-pollie (pillbug), rolly-polly, tumblebug, doodlebug

The second way sowbugs and pillbugs get noticed is by sheer numbers. They can sometimes occur in such high numbers that they alarm people. They may enter houses following rains when outside soils become saturated. Sowbugs found indoors won't cause any damage and can be simply swept up. Pillbugs roll into a ball when distrubed, sowbugs do not roll up this way.

Can sowbugs and pillbugs be managed?

In one sense high numbers of these critters is a good thing -- it means that your garden soils are rich in organic matter and healthy. You can reduce the populations, however, by reducing the amount of organic matter that you add to the garden and cutting back on the frequency of watering. If the soil is allowed to go through natural dry/wet cycle sowbug and pillbug numbers will be reduced.